At a briefing after the company announced its fiscal second-quarter earnings Tuesday, Nomura Chief Financial Officer Shigesuke Kashiwagi said the firm was still upbeat about the market and about retail appetite for investments, despite a recent downturn and the possible impact of a sales-tax increase expected next year.

In April, the government raised the national sales tax to 8% from 5%, a move that slowed economic growth.

“We still expect the Nikkei can rise to 17,000 by the year-end,” Mr. Kashiwagi said. “Yes, we see the tax increase as a big factor, but employment is picking up and corporate capital spending is increasing, so the economy is improving overall.”

The benchmark Nikkei Stock Average rose 6.7% in the July-September quarter before declining 5% in October, the primary victim in Asia of volatility that has rattled global markets. It closed at 15329.91 on Tuesday.

Nomura’s net profit more than doubled to ¥52.87 billion ($490 million), from ¥19.86 billion in the April-June period. It also surpassed the ¥38.11 billion profit in the same period a year earlier. A survey of eight analysts pointed to a result of ¥42.6 billion.

Some Western banks have scaled back trading operations because of more stringent capital requirements, but Mr. Kashiwagi said Nomura’s strong capital base allows it to do business more freely.

Earlier this month, Moody’s Investors Service raised Nomura’s long-term credit rating by two notches to Baa 1 from Baa 3. The core brokerage unit, Nomura Securities, was upgraded two notches to A3 from Baa 2.

The ratings change “will help us explore new customers, including central banks, for derivatives trading,” Mr. Kashiwagi said. The upgrade is also expected to curb Nomura’s borrowing costs internationally.

Nomura also said business in Asia and Europe helped its overseas operations swing to a profit of ¥3.7 billion on a pretax basis, from a loss of ¥17.14 billion in the earlier quarter.

In Europe, Nomura returned to the black for the first time in nearly in two years. In the U.S., however, it booked a ¥6.8 billion pretax loss due to weakness in fixed-income trading.

July-September revenue increased 0.8% on a net basis to ¥373.83 billion, while revenue from the retail business, which accounts for about a third of the total, climbed 10% from the previous quarter to ¥117.9 billion. The total was down 1% from the year-earlier period.

The increase in revenue was partially driven by a campaign to attract investors under a new tax-free investment program called Nippon Individual Savings Accounts, or NISAs.

Meanwhile, revenue from the wholesale business—investment banking and trading—grew slightly to ¥190.6 billion from ¥188.9 billion in the previous quarter.

Unlike some U.S. banks, such as
Goldman Sachs
Group Inc., Nomura didn’t see strong revenue from fixed-income trading, an area on which it has been focusing. Earnings from fixed income, part of the wholesale business, were ¥104 billion, down 0.5% from the previous quarter.

Nomura said the slump in that area was mainly due to weakness in the U.S. and Europe, offset by a jump in trading revenue in Japan and elsewhere in Asia.